1. The Field of the Invention
The present invention relates to electrical connectors for use with media plugs and, more specifically, sliding pin assemblies configured to establish electrical communication between a media plug and a PCB.
2. Present State of the Art
Electrical apparatus, such as personal computers, cellular telephones, and personal information managers (PIMs), are becoming increasingly dependent upon their ability to electrically communicate or share information with other electrical apparatus. To facilitate this electrical communication, a variety of different types of electrical couplers have been developed. An electrical coupler includes a plug and a corresponding jack or connector. The jack typically includes an aperture or socket configured to receive the plug so as to establish electrical communication therebetween.
Select types of electrical couplers have been designed for use with PC cards. A PC card is a small thin card typically having a standard size. A first type of connector is formed at one end of the PC card and is configured to couple with the electrical apparatus. A second type of connector or jack is formed at the opposing end of the PC card and is configured to couple with a desired outside line such as a telephone line or a network line. Disposed within the PC card is a circuit board providing the necessary circuitry to perform one or more intended functions. For example, in one type of PC card, the circuit board comprises a modem which enables the electrical apparatus to receive and transmit information over telephone lines. In another PC card, the circuit board enables the electrical apparatus to receive and transmit information with a network system over a network cable.
One conventional type of jack used for connecting a PC card to an exterior line comprises a thin plate which is slidably mounted to the PC card. The plate has a top surface with an aperture formed therein. A plurality of short contact pins are rigidly mounted to the thin plate. Each contact pin has a first end that is freely exposed within the aperture and an opposed second end mounted to the plate. A flexible wire ribbon has a first end that is soldered to the second end of the contact pins and an opposing second end that is soldered to contacts on the circuit board within the PC card.
The thin plate can selectively slide between an extended position and a retracted position. In the extended position, the aperture is exposed such that a corresponding plug, for example an RJ-11, commonly referred to as a telephone plug, can be received therein. The plug pushes against the contact pins so as to establish electrical contact therewith. As a result, electrical communication is established from the plug, through the contact pins and flexible wire ribbon, to the circuit board. When not in use, the thin plate is retracted by sliding back within the PC card such that the aperture is not exposed. The ability to repeatedly slide the plate between the extended and retracted position while maintaining electrical communication between the pins and the circuit board is attributed to the flexible wire ribbon. That is, the wire ribbon freely bends or folds as the plate is retracted and then unfolds as the plate is extended.
Although effective in establishing electrical communication between a plug and a circuit board of a PC card, the above described sliding jack has several drawbacks. For example, repeated movement of the plate between the retracted and extended position produces stresses on the flexible wire ribbon and its soldered contacts. These stresses eventually result in fatigue failure of the wire ribbon and/or the solder contact. Moreover, during the manufacturing process, soldering requires high temperatures which potentially serve to deform the materials used in the flexible wire ribbon. Often these materials are plastic and can be catastrophically destroyed. Additionally, during the solder manufacturing process, too much solder applied at areas of electrical connections can cause the solder to spread and potentially cause electrical shorts.
Furthermore, since the slidable plate is fixedly attached to the circuit board by the flexible wire ribbon, it is difficult if not impossible to replace or repair the plate or pins. Thus if any element of the electrical coupling system is damaged, either the PC card must be returned to the manufacturer for repair, or a new PC card must be purchased.
Still other limitations exist within the manufacturing process. The flexible wire ribbon is positioned on the circuit board by techniques commonly known as "pick-and-place." Although generally effective, the pick-and-place process often "loses" the flexible wire ribbon as it is being positioned on the PCB. This losing then disrupts the manufacturing line, especially automated ones. It can also cause the flexible wire ribbon to be incorrectly positioned on the PCB. Moreover, pick-and-place may overstress the wires or conductors within the ribbon when maneuvering. This can potentially causes failure of the conductors.
Another inherent limitation is the spatial arrangement that must exist within the communications card to allow the sliding plate to freely move without constriction from the flexible wire ribbon. That is, a relatively large free area must be formed within the card to enable the wire ribbon to freely move and flex. This free area limits the size of the circuit board and the number of electrical components that can be positioned thereon.
Another problem associated with conventional retractable jacks relates to the pin configuration. That is, the second end of each pin is rigidly secured to the plate so as to suspend the opposing free end within the aperture. Insertion of the plug downwardly bends the pins. The pins then resiliently flex back to their original configuration upon removal of the plug. Repeated insertion and removal of the plug can produce localized stresses within the pins and eventually result in their fatigue failure. Furthermore, the pins can be easily bent beyond their elastic limit. This permanent bending of the pins can prevent them from biasing against the plug.